Apparatus for making tissue type paper



' Jan. 25, 1944.

E. E. BERRY APPARATUS FOR MAKING TISSUE TYPE PAPER Filed Dec. 9, 1940 mmNu 6324 Esme r.

ow a Patented Jan. 25, 1944 V S ES PATENT OFFICE" a 2 2,340,103. a Y

Earl n. Berry, Beloit, assignmio Beloit Iron Works, neioitlwia, acorporation of Wisoonsln This invention relates to a paper makingmachine especially adapted for the production of soft toilet tissue typepapers and more particularly relates to an inverted pick-up felt machinedisposed between the forming part and the drier section of a papermaking machine.

In conventional pick-up felt arrangements for paper making machines theweb is picked up from the forming surface of the paper making machineonto a pick-up felt. The transfer from the forming surface to the feltis usually accomplished by running the felt between top and bottob couchrolls and pressing the felt against the newly formed web on the formingwire trained around the bottom couch roll. The felt and web is thenusually passed through 'a press roll assembly together with a coveringfelt for protecting the exposed face of the web.

If'a suction press roll assembly is used, suction must be appliedthrough the bottom or covering felt since the pick-up felt is usuallyquite impervious and resists passage of water and air therethrough. As aresult, the suction will tend to transfer the web to the bottom orprotecting felt and then, as the web passes through the nip of theassembly, it is again squeezed against the pick-up felt so that it canfollow this felt the drier section of the machine.

If a suction top couch is used the pick-up felt must be of a more openor pervious type so that suction could be effective to transfer the webonto the felt. However, if such an open pick-up felt is used. it willnot retain the web to a satisfactory degree and the web will betransferred to the bottom felt or covering felt in- Z stead of followingthe pick-up felt to the drier section.

Now, the present invention provides for the use of a pick-up felt forconveying the web from the forming section to the first press assembly,together with the use of a more pervious felt for conveying the web fromthis first press assembly to the drying section and through additionalpress assemblies if desired.

The use of the two felts for different convey! Application December 9,1940, Serial No. 369,219

3 Claims. (on. 92-49) Another advantage is that higher pressures can beused at the first press roll assembly receiving both felts therethroughso that the web can be dewatered to a greater extent than was heretoforepossible when it was necessary .to

retain the web on the pick-up felt. In accord-' ance with the presentinvention, high pressures at the first press roll assembly insuretransfer to the bottom felt and additional water removal.

It is, then, an object of this invention to provide an inverted pick-upfelt machine forhandling fragile paper webs between the forming sectionand the drying section of a paper making'machine.

Another object of this invention is to provide a paper making machinecapable of producing fragile, delicate soft tissue papers withoutsacrificing efliciency in the press roll section of the machine.

A still further object of this invention is to utilize separate pick-upfelts and drying felts in a press roll section of a paper makingmamaking tissue-type papers by extracting higher percentages of waterfrom the newly formed tissue by means of suction and pressure. andthereby decrease the drying time.

A further object of this invention is to provide a paper making machineof the Yankee type wherein a pick-up felt transfers the sheet from theforming part to a suction press. and wherein a more liquid-pervious feltconveys the sheet from the suction press to the top of the Yankee drierdrum.

A further object of the invention 'is to pro vide a Yankee type papermaking machine wherein the forming part and press roll sections aremounted at a level above the Yankee drier drum Other and further objectsof' the invention will be apparent to those skilled in the art from "thefollowing detailed description of the an nexed sheet of drawings which.by way of example, discloses a preferredembodiment of the invention.

On the drawing:

Figure 1- is a diagrammatic side elevational view of a machine embodyingthe principles of this invention. I

Figurez is a cross-sectional view, greatly en= larged, illustrating thecharacteristics of the -shiftably mounted bearings 3i pick-up felt usedin the machines 'of this in-' vention.

Figure 3 is a cross-sectional view, greatly enlarged, illustrating themore open bottom felt or drying felt used on machines of this invention.

As shown on the drawing:

In Figure 1 the reference character A designates generallythe formingpart or wet end of the-paper machine, the reference character Bdesignates the press roll section of the machine, and the referencecharacter C designates generally the Yankee drier drum of the machine.

The wet end A and the press roll section B are mounted on a fioorsupported by pillars ll above a sub-fioor or basement l2. The Yankeedrier C is mounted on end supports it carrying bearings such as 14 torotatably mount the drier drum l5 at a level beneath the press rollsection B. A platform l6 can be provided ad- Jacent the side of thedrier drum l5 and stairs l1 canbe provided to connect the platform Itwith the floor I0.

The forming section A includes a forming wire trained between a breastroll 2| and a couch r011 22 and having its upper run directed over tablerolls 23, suction boxes 24 and the like. A head box 25 supplies stock tothe upper run of the forming wire 20 adjacent the breast roll endthereof and this head box 25 canreceive the paper stock from oppositelyflowing streams of stock in conduits 25.

A suction couch roll 21 is rotatably mounted on arms such as 28 whichare pivotally supported from pedestals such as 23 and adjusted by meansof turnbuckles 30 or other adjusting mechanisms. The upper suction couch21 can be shifted on the arms such as 28 by means of screws such as 32.

The roll 21 has a perforated periphery and has spaced suction heads 33and 34 mounted therein immediately before and immediately after the nipbetween the rolls 22 and 21.

A first suctionpress assembly including a suction roll 35 mounted onpedestals such as 35 from the floor ill and a top press roll31 mount--ed on arms such as 34 pivotally mounted on brackets such as 39 dependingfrom an overhead support 40. The overhead support 43 is carried on thepedestals such as 29 and additional pedestals such as 4|.

The suction roll 35 has the suction box 350 thereof extending throughthe nip between the rolls 35 and 31 to cover the nip area and areasimmediately before and after the nip areas. The roll 31 is urged againstthe roll 35 by means of hydraulic jacks such as 42 depending from theoverhead support and having the piston rods such as 43 thereof connectedto the free ends of the arms such as. The jacks 42 are effective toexert a downward pressure or a lifting force so that the pressure in thenip between the rolls 35 and 31 can be accurately controlled.

A second suction press assembly is positioned in the press section B andincludes a lower suction roll 44 rotatably mounted on bearings carriedby brackets such as 45 which, in turn, are carried by the pedestals suchas 4|.

A top press roll 45 cooperates with the suction roll 44. The roll 46' iscarried on arms such as 41 which are pivotally mounted on the pedestalssuch as 4| and moved toward and away from the suction roll 44 by meansof hyadjusted by p draullc jacks such as 48 having their piston rods 48depending from the topsupport B. A transfer roll 50 is rotatably mountedon bearings carried by arms such as 51 which are pivoted to the,pedestals such as 4| to extend laterally from the pedestals in adirection opposite to the arms 41 and brackets 45. Lift screw devicessuch as 52 are pivotally connected to the outer ends of the arms such as5| and are carried by arms such as 53 which are pivotaily connected tobrackets such as 54 carried by the pedestals 41. The transfer roll 50can therefore be raised and. lowered toward and away from thedrier'drumi5.

In accordance with this invention a pick-up felt 55 having an efficientsinged pick-up nap 55a and a rather fine weave 55b, is trained aroundthe top couch roll 21 and top press roll 31 for picking up a webfrom-the forming wire 20 and conveying the web on the under side thereofto the first suction press assembly. The pick-up felt 55 is thendirected around the roll 31 away from the web and over a guide roll 55mounted above the top support 40. A horizontal suction press rollassembly including a suction roll 51 and a plain press roll 58 mountedon top of the support B next receives the felt 55 in a downwarddirection through the nip provided thereby. The suction roll 51 has asuction box 510. in advance of the nip for maindirected around'the guideroll 63 and thenceupwardly over a guide roll 54 to a stretcher roll 55.Additional guide rolls 55 and 51 then guid the felt back to the suctioncouch 21.-

A drying felt or bottom felt 10 having a shorter and coarser nap 10a anda more open weave 10b than the nap and weave of the pickup felt 55, istrained over the suction rolls 35 and 44, around the transfer roll 50and thence over guide rolls" and 12 to travel above the drier drum l5 inthe path of heat radiation and convectiontherefrom. Radiated heat fromthe'drum will tend to warm up the water in the felt and make it easierto extract by pressure. From the guide roll 12 the felt 10 is directedthrough an opening Ilia in the floor ll, around a stretcher roll 13rotatably mounted in the basement beneath the press section B, backthrough the opening Ilia and through the nip of a horizontal press r011assembly. The hori-- zontal press roll assembly comprises a roll 15mounted on bearings carried by pedestals such as 15 at the ends of theopening [0a, and a roll 11 pivotally mounted on pedestals such as 12.The bearing supports for the rolls 15 and 11 have upwardly extendingarms 19 and respectively connected by springs such as 8| or other meansfor urging the roll 11 toward the roll 15 to create pressure in the nip.

After passage upwardly through the nip between the rolls 15 and 11, thefelt 15 is directed back over the'suction roll 35.

A web of paper W partially formed on the forming wire 20 is picked up bythe pick-up felt The roll 53.

55 as the web and wire advance through the nip between the top andbottom couch rolls 22 and 21. Y

The suction box 33 in the top couch roll 21 will maintain the nip areain a substantially dry condition and will prevent a crushing of thedelicate web as it passes throughthe nip. The pressure existing in thenip between the rolls 22 and 21 will effect a transfer of the web fromthe wire to the pick-up felt and the second suction box 34 locatedimmediately after the nip will assist in retaining the web on thepick-up felt. The web then travels, while supported on the under side ofthe pick'-up felt, from the couch roll to the first suction press, whereit is covered bythe bottom felt I0.

The press rolls and 31 of the first suction press can be urged togetherto create a higher nip pressure than was heretofore practical in thehandling of tissue-type papers in the conventional press roll section.This high pressure will effect a transfer of the web from the pick-upfelt 55. to the bottom felt Ill. The suction box 35a extending throughthe nip area will assist in this transferring of the web and willmaintain a dry nip area to prevent crushing of the web.

The pick-up felt 55 is then conveyed away from the web immediately afterthe two felts with the web therebetween have been passed through th nipof the first suction press assembly.

The bottom felt 10 then supports the web on the top surface thereof andcarries the samethrough the second suction press assembly where it isagain subjected to suction and pressure for elimination of additionalamounts of water.

The web and felt 10, after passing through the second suction pressassembly are trained around and under the transfer roll 50 so that theweb will be suspended from the underface of the felt. The transfer roll50 is urged against the drier drum l and the web will be transferred tothe top of the drum. The drum rotates in a counter-clockwise directionas indicated by the arrow and, has the periphery thereof heated tovaporize the remaining moisture in the web.

An excellent transfer from the felt 'I0 to the drier drum I5 is insuredbecause the felt does not have as great an aflinity for the web as thepick-up felt 55, and because gravity assists in the transfer inasmuch asthe web, at the point of transfer, is on the underface of the felt l0and is deposited on top of the roll l5. Heretofore the transfer to aYankee drier drum was efiected at the bottom of the drum. As a resultthe web had to be pasted onto the drum under considerable pressure sothat it would not fall away from the drum as it was carried upwardlyaway from the transfer roll. In the present installation such highpressures are not necessary and gravity is used to aid the transfer.

The web then travels with the roll I5 for almost a complete revolutionthereof and is doctored ofl of the roll by means of a doctor 82,.

Before the surface of the drum I5 recontacts the web, it is preferablycleaned by a scraper or wiping device 83.

The machines of the present invention are far more efficient and can beoperated at higher speeds than heretofore known pick-up type machines.Thus high speed and great efficiency are made possible by the use of atop pick-up felt designed mainly for pick-up efficiency and a bottomconveying felt designed mainly for watertransfer efficiency whereasheretofore a single felt was used and had to be a compromise in everyrespect, so that it was capable of picking up the web and also capableof permitting water transfer therethrough. The use of the two differentfelts to carry out their respective functions has made possible the useof higher pressures in the press section and better transfer at thedrier section. Thefeature of mounting the drier drum at a level beneaththe transfer roll instead of above the transfer roll has also materiallyincreased the transfer efficiency.

The papers produced by machines of this invention are superior to thoseproduced on conventional pick-up machines since-both sides of the sheetare contacted with felts and the top sides of the sheet can be subjectedto direct ac \tion by a press roll as it is conveyed by the under feltto the drier drum section. This same top side of the sheet is thencontacted with the drier drum.

It will, of course, be understood that various details of the inventionmay be varied through a wire range without departing from the principlesof this invention and it is, therefore, not the purpose to limit thepatent granted hereon otherwise than necessitated by'the scope of theappended claims.

I claim as my invention:

1. In a paper making machine having a forming wire trained around a;couch roll and a top suction couch roll cooperating with said firstmentioned couch roll, the improvements of a drier drum rotatably mountedat a level beneath the level of the couch roll in spaced lateralrelation from the couch roll, a suction press roll assembly, a pick-upfelt trained through the nip between the couch rolls and a nip betweenthe rolls of the suction press roll assembly for picking up a web ofpaper from said forming wire to convey the web to the press rollassembly, a

an transfer roll cooperating with the top portion of said drier drum onthe side thereof remote from the formin wire, a bottom liquid-perviousfelt trained through a nip of said press assembly, around said transferroll and above the drier drum in the path of heat convection from thedrum for covering the web on the pick-up felt, for conveying the webfrom the press assembly to the drier drum, and for being heated by thedrier drum and a suction box acting through said bottom felt at the niparea of said press assembly to transfer the web from the pick-up felt tothe bottom felt.

2. In a paper making machine, top and bottom couch rolls defining a niptherebetween, a forming wire trained around said bottom couch roll, apick-up felt trained around said top couch roll through said nip toreceive a paper web from the forming wire, a suction head'in said topcouch roll in advance of the nip to dry the/nip, a

no second suction head in said top couch roll positioned after the nipto act through said pick-up felt for retaining the web on the felt, afirst suction press roll assembly including a top roll and a bottomsuction roll providing a suc- 85 tion nip receiving the pick-up felt andweb therethrough, a second-suction press roll assembly including a toproll and a bottom suction roll providing a second suction nip, atransfer roll, a drier drum beneath the transfer roll, a bottom dryingfelt trained through the nips of both suction presses, around thetransfer roll and over the drier drum in the path of heat convectionfrom the drum, a press assembly receiving the bottom felt alonetherethrough, and another press assembly receiving the pick-upfelt alone4 au ios drieriiriunon'thesidethereofremotefromthe'v therethroughwhereby successive felts will engage opposite faces of the paper web enroute to the drier drum and the felts will be dewatered by said pressassemblies between each engagement with the web.

3. In a p per making machine including a forming part and a drier drumin spaced longitudinal relation from the forming part, the improvementscomprising a top pick-up felt receiving a web from said forming part onthe underi'ace thereof, a press roll assembly receiving said pick-upfelt and web thereon through a nip thereof, a bottom 'liquid-perviousfelt covering said web as it passes through said nip, means transferringsaid web from the pick-up felt to the liquld-pervious felt, a transferroll above said forming part receiving the liquid-pervious felt and webtherearound to deposit the web on the drummeanstorotatethedrumforcarryingthe webaroundthetopportionthereofinadirection toward theforming part and around the lower portion thereof in a direction awayfrom the forming part. meanaon the same side of thedrumaathetransferrolltoremovethewebfrom the drum. guide means directingsaid liquid-pervious felt' alone over the drier drum in the path of heatconvection therefrom to heat liquid retained in the felt, and a pressassembly receiving the felt therethrough to extract the heated liq-

